When logging into UW-Madison services using your NetID, you must have cookies enabled in order to be able to login successfully. If cookies are disabled, you will get a "NetID Login System Failure" error page. This document explains how to enable cookies on iOS devices to fix or prevent this problem.
If cookies are disabled when attempting to login to services using the NetID Login Service, then you will likely get a 'Login System Failure' error as shown below.
To fix this issue, you should verify that cookies are enabled in iOS. You can do so by doing the following:
Once this is done, you should no longer receive the "NetID Login System Failure" error when logging into a NetID-protected service on your iPhone, iPod Touch, or iPad.